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authorDave Airlie <airlied@redhat.com>2014-12-23 08:24:26 +1000
committerDave Airlie <airlied@redhat.com>2014-12-23 08:24:26 +1000
commitfc556fb64e3a4cdc6b764079a98e3cfb85d89c1f (patch)
tree4ee704df2b9952943f4f4fc4db3704549fbe97b1 /drivers/char
parenta548a838a1f770a55ec3e750f36ba281d7f4ab2e (diff)
parent93396d0f9c027654eb09151d2e22fe78a39feedb (diff)
Merge tag 'drm/tegra/for-3.19-rc1-fixes' of git://people.freedesktop.org/~tagr/linux into drm-fixes
drm/tegra: Fixes for v3.19-rc1 This is a set of fixes for two regressions and one bug in the IOMMU mapping code. It turns out that all of these issues turn up primarily on Tegra30 hardware. The IOMMU mapping bug only manifests on buffers that aren't multiples of the page size. I happened to be testing HDMI with 1080p while writing the code and framebuffers for that happen to fit exactly within 2025 pages of 4 KiB each. One of the regressions is caused by the IOMMU code allocating pages from shmem which can have associated cache lines. If the pages aren't flushed then these cache lines may be flushed later on and cause framebuffer corruption. I'm not sure why I didn't see this before. Perhaps the board that I was using had enough RAM so that the pages shmem would hand out had a better chance of being unused. Or maybe I didn't look too closely. The fix for this is to fake up an SG table so that it can be passed to the DMA API. Ideally this would use drm_clflush_*(), but implementing that for ARM causes DRM to fail to build as a module since some of the low-level cache maintenance functions aren't exported. Hopefully we can get a suitable API exported on ARM for the next release. The second regression is caused by a mismatch between the hardware pipe number and the CRTC's DRM index. These were used inconsistently, which could cause one code location to call drm_vblank_get() with a different pipe than the corresponding drm_vblank_put(), thereby causing the reference count to become unbalanced. Alexandre also reported a possible race condition related to this, which this series also fixes. * tag 'drm/tegra/for-3.19-rc1-fixes' of git://people.freedesktop.org/~tagr/linux: drm/tegra: dc: Select root window for event dispatch drm/tegra: gem: Use the proper size for GEM objects drm/tegra: gem: Flush buffer objects upon allocation drm/tegra: dc: Fix a potential race on page-flip completion drm/tegra: dc: Consistently use the same pipe drm/irq: Add drm_crtc_vblank_count() drm/irq: Add drm_crtc_handle_vblank() drm/irq: Add drm_crtc_send_vblank_event()
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